The Value Of Ultrasonic Elastography And TI-RADS In Differentiation Diagnosis Of Thyroid Nodules

Background and objectiveIn recent years, scholars at home and abroad have found that the incidence ofmalignant thyroid nodules showed an increasing trend, and the rise is among the first of all cancers.High-resolution ultrasound is the most sensitive imaging ins-pection for thyroid nodules.To date, the ultrasound technology commonly used in clinical is gray-scale ultrasound and color Doppler ultrasound. They obtain a comprehensive evaluation by observing the number, size, shape, boundary, inter-nalecho, with or without calcification and blood flow of thyroid nodule. However, the sonographic appearance of thyroid nodules is very complex.Besides sonographic appearance of benign and malignant lesions may overlap.Therefore, the diagnostic accuracy of ultrasound for thyroid nodules is affected. Meanwhile, the qualitative diagnosis of ultrasound for thyroid nodules is also affected by subjective factors of the diagnostician, demanding on the operator’s experience.So often the same patient diagnosis by different doctors may come to different conclusions. Besides due to ambiguous description of lesions, it affects the communication between the sonographer and the clinician.There is also the above problems in the breast nodules. In 1992 the United States develop a guide file— Breast imaging reporting and data syste(BI-RADS),expected to achieve standatdization of ultraso-und description of breast nodules,and improve the accuracy of ultrasound diagnosis. It has been made widely recognized by clinicians.By learning from the BI-RADS,foreign scholars proposed thyroid imaging reporting and data system(TI-RADS),expected to achieve standatdization of ultrasound description of thyroid nodules,and improve the accuracy of ultrasound diagnosis. But the TI-RADS is still in the preliminary application stage.Whether it can improve the diagnostic accuracy of thyroid nodules remains to be further studied.Ultrasound elastography (UE) is a hot technology of the ultrasonic field developed in recent years. It is based on the hardness of the lesion to determine it is benign or malignant. Its diagnostic value has been recognition by clinicians, especially application in the breast nodules are quite mature. Currently, there were some reports about its application in thyroid nodules, but not yet mature.Besides, the size and location of the nodules, calcification and blooding can affect the diagnostic accuracy of the UE.The main purpose of this study is to explore the application value of the UE and the TI-RADS classification in the thyroid nodules, expect to improve the accuracy of ultrasound in the diagnosis of thyroid nodules and provide better serbices for clinical.Subjects and Methods125 patients with 190 thyroid nodules in the second affiliated Hospital of Zhengzhou University from June 2009 to Jnne 2011 were examined by conventional ultrasound and UE.All the nodules had the cytological or histological pathology results.According to the diameter of the thyroid nodules, they were divided into <10mm group and >10mm.UE and the TI-RADS diagnostic criteria assess the nature of thyroid nodules.The elastic image classification 1-2 considered as benign,3-4 considered as malignant. TI-RADS classificationg of grade 1-3 judged benign,4-5 considered as maliganant.The two methods of ultrasound results were compared with histologic findings.Receiver operating characteristic curve (ROC) was established by taking pathologic findings as the gold standard to compare the value of TI-RADS and UE in differentiation of thyroid nodules.Besides, the size of thyroid nodules also was comparised.Meanwhile combined the two methods’builded ROC curves to assess the value of ultrasound of qualitative diagnosis of thyroid nodules.Results1 In the nodule diameter≤10mm, the UE diagnostic accuracy higher than TI-RADS (χ2=4.614,P<0.05), while in the nodule diameter> 10mm group, TI-RADS diagnostic accuracy is higher than the UE(χ2=3.956, P<0.05).2 Sensitivity, specificity, accuracy, positive predictive value and negative predictive values of Ultrasound elastography was 88%,92%,91%,82%,95%. sensitivity, specificity, accuracy, positive predictive value and negative predictive values of TI-RADS diagnostic criteria was 72%,84%,81%,66%,88% respectibely.Comparison between the two methods, the sensitivity, accuracy, positive predictive value, negative predictive value were statistically significant,χ2 were 4.412,7.674,4.001,3.945 respectibely.The combination of the two kinds of methods, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value was 91%,94%,93%,87% and 96% respectibely, and all higher than the single method.3 AUC of Ultrasonic elastography was 0.926, area of standard error was 0.024, and 95% confidence interval was (0.880,0.973). TI-RADS diag-nosis of AUC is 0.869, area of standard error was 0.027, and 95% confidence interval was (0.816,0.921). Compared the area under the ROC curve of two ways, there was significantly different(Z=2.5,P=0.005).The AUC for the combination of the two methods was 0.973,meanwhile compared with the two methods respectibely, there was significantly different(Z was 2.4 and 3.9,P<0.01).Condusion1 TI-RADS can play an important role in standardized and specification ul-trasonic term;2 UE is a new technology for the indentification of benign and malignant thyroid nodules.The accuracy of qualitative diagnosis of UE is higher than the TI-RADS, especially in the nodules of diameter<10mm.3 UE is a useful complement to the TI-RADS.The combination of the two methods can improve diagnostic accuracy.